黄河中下游悬浮颗粒物多核素时空分布特征及其指示意义

天然放射性核素（238U、40K、226Ra、228Ra、7Be、210Pb_xs等）信息对于认识河流颗粒物的来源及输运过程具有重要的指示意义，然而目前关于河流悬浮颗粒物（SPM）的核素研究尚不多见。本研究分析了黄河中、下游水体悬浮颗粒物中各种天然放射性核素的活度水平及时空分布特征，发现春季颗粒物的238U、40K、226Ra、228Ra、7Be和210Pb_xs活度分别为26.86～119.57 Bq/kg、619.50～835.62 Bq/kg、12.88～55.51 Bq/kg、24.55～82.61 Bq/kg、0.24～39.47 Bq/kg和0.92～18.78 Bq/kg，秋季分别为40.54～73.96 Bq/kg、804.95～1023.12 Bq/kg、31.24～47.68 Bq/kg、57.92～77.95 Bq/kg、0.98～30.50 Bq/kg和12.60～31.33 Bq/kg。对比发现，除7Be在两次调查时表现出相似的变化范围和趋势外，其他各种核素的比活度整体上均表现为春季高于秋季的季节特征。就核素的含量及比值的空间分布而言，黄河小浪底、开封和将军渡3个河段均存在数值异常的现象，推测是这3处区域的物质来源、颗粒物粒径及成分组成不同于其他区域所致。

Spatio-temporal distributions and indications of multi-nuclides on suspended particulate matters in the middle and lower reaches of the Yellow River

Natural radionuclides (238U, 40K, 226Ra, 228Ra, 7Be, 210Pb_xs, etc.) are important tracers for understanding the sources and transport process of particulate matters. However, studies about the nuclides on suspended particulate matters (SPM) in rivers are still rare thus far. In this study, we analyzed the activity levels and spatial-temporal distribution characteristics of multiple natural radionuclides on SPM in the middle and lower reaches of the Yellow River. It was found that the activity ranges of 238U, 40K, 226Ra, 228Ra, 7Be and 210Pb_xs on SPM in spring were 26.86～119.57 Bq/kg, 619.50～835.62 Bq/kg, 12.88～55.51 Bq/kg, 24.55～82.61 Bq/kg, 0.24～39.47 Bq/kg, and 0.92～18.78 Bq/kg; and were 40.54～73.96 Bq/kg, 804.95～1023.12 Bq/kg, 31.24～47.68 Bq/kg, 57.92～77.95 Bq/kg, 0.98～30.50 Bq/kg, and 12.60～31.33 Bq/kg in autumn, respectively. Both the ranges and trends of 7Be were similar in the two surveys. The specific activities of all other nuclides in spring were higher than which in autumn. In terms of the spatial distribution of various nuclides contents and ratios, there were significant anomalies in the three regions of Xiaolangdi, Kaifeng and Jiangjundu. It was speculated that this may be due to the changes of material source, particle size and compositions.